package org.point.common.util;

import java.security.InvalidAlgorithmParameterException;
import java.security.Key;
import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * 
 * 加密解密工具包
 */

public class CypToUtil {
	
	private static final Log log = LogFactory.getLog(CypToUtil.class);

	public static final String ALGORITHM_DES = "DES/CBC/PKCS5Padding";

	/**
	 * 
	 * DES算法，加密
	 * 
	 * 
	 * 
	 * @param data
	 *            待加密字符串
	 * 
	 * @param key
	 *            加密私钥，长度不能够小于8位
	 * 
	 * @return 加密后的字节数组，一般结合Base64编码使用
	 * 
	 * @throws InvalidAlgorithmParameterException
	 * 
	 * @throws Exception
	 */

	public static String encode(String key, String data) {

		if (data == null)

			return null;

		try {

			DESKeySpec dks = new DESKeySpec(key.getBytes());

			SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");

			// key的长度不能够小于8位字节

			Key secretKey = keyFactory.generateSecret(dks);

			Cipher cipher = Cipher.getInstance(ALGORITHM_DES);

			IvParameterSpec iv = new IvParameterSpec("12345678".getBytes());

			AlgorithmParameterSpec paramSpec = iv;

			cipher.init(Cipher.ENCRYPT_MODE, secretKey, paramSpec);

			byte[] bytes = cipher.doFinal(data.getBytes());

			return byte2hex(bytes);

		} catch (Exception e) {

			log.error(e.getMessage(), e);
			
			return data;

		}

	}

	/**
	 * 
	 * DES算法，解密
	 * 
	 * 
	 * 
	 * @param data
	 *            待解密字符串
	 * 
	 * @param key
	 *            解密私钥，长度不能够小于8位
	 * 
	 * @return 解密后的字节数组
	 * 
	 * @throws Exception
	 *             异常
	 */

	public static String decode(String key, String data) {

		if (data == null)

			return null;

		try {

			DESKeySpec dks = new DESKeySpec(key.getBytes());

			SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");

			// key的长度不能够小于8位字节

			Key secretKey = keyFactory.generateSecret(dks);

			Cipher cipher = Cipher.getInstance(ALGORITHM_DES);

			IvParameterSpec iv = new IvParameterSpec("12345678".getBytes());

			AlgorithmParameterSpec paramSpec = iv;

			cipher.init(Cipher.DECRYPT_MODE, secretKey, paramSpec);

			return new String(cipher.doFinal(hex2byte(data.getBytes())));

		} catch (Exception e) {

			log.error(e.getMessage(), e);

			return data;

		}

	}

	/**
	 * 
	 * 二行制转字符串
	 * 
	 * @param b
	 * 
	 * @return
	 */

	private static String byte2hex(byte[] b) {

		StringBuilder hs = new StringBuilder();

		String stmp;

		for (int n = 0; b != null && n < b.length; n++) {

			stmp = Integer.toHexString(b[n] & 0XFF);

			if (stmp.length() == 1)

				hs.append('0');

			hs.append(stmp);

		}

		return hs.toString().toUpperCase();

	}

	private static byte[] hex2byte(byte[] b) {

		if ((b.length % 2) != 0)

			throw new IllegalArgumentException();

		byte[] b2 = new byte[b.length / 2];

		for (int n = 0; n < b.length; n += 2) {

			String item = new String(b, n, 2);

			b2[n / 2] = (byte) Integer.parseInt(item, 16);

		}

		return b2;

	}
	
	public static void main(String[] args) {
		//String str = CypToUtil.encode("SECRET_KEY", "Hello World!");
		//System.out.println(str);
		//String ostr = CypToUtil.decode("SECRET_KEY", str);
		//System.out.println(ostr);
	}

}
